Lake Bistineau Update - Sept. 22, 2010

Several weeks ago, the gates at the control structure on Lake Bistineau were closed in an effort to slowly increase water levels. Unlike last year, there has been very little precipitation in the watersheds, resulting in no water level increase above the 7 foot drawdown capacity.

As expected, giant salvinia, especially in protected areas/pockets has increased in coverage.

The gates will remain closed until water levels rise and salvinia coverage is evaluated at the increased water levels. When water levels allow, we plan to initiate water level fluctuations to strand the salvinia. Please note that water fluctuation efforts may occur prior to the lake reaching pool stage. Rain events drive water levels in the lake. Therefore, the department cannot provide a timeframe for fluctuation events based on this unknown.

Part of our plan also includes continued herbicide applications on the lake. However, maneuvering equipment for these treatments is tedious and dangerous due to low lake levels and stumpage. Currently, some shallow areas appear to be inundated with the plant. Many of these areas remain inaccessible to herbicide treatments, but once lake levels rise, the salvinia will disperse over a much larger space. As the plants move to new areas, we anticipate they will be more susceptible to stranding due to water level manipulation in combination with herbicide treatments.

Webster Parish has submitted a funding assistance request to develop a new boating access facility at the Port of Bistineau to allow boating access during drawdown periods. The department will consider this request once parish officials submit a finalized application.

Those interested in removing cypress trees during the drawdown period are asked to contact James Seales (318) 371-3063 in our Minden office. We will consider issuance of a permit on a case by case basis, based on the need. We require that all trees be cut to the mud line and removed from the lake.

Mapping of the lake bottom is not expected to be complete until the lake level reaches pool stage sometime this winter. A contour map is necessary to finish our assessment of shallow lagoons in preparation of our request to the U.S. Army Corps of Engineers to conduct specific dirt work. These lagoons serve as an exceptional habitat for salvinia growth. In our plan, we discuss the need to address those areas cut off from draining during drawdown events.

A fly-over of the lake is planned in the near future to help us understand more about giant salvinia coverage during the drawdown and identify those areas cut off from draining.

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